July 28, 2011

Tooth Sealants: Sealing Is Not Just For Driveways

Asphalt is a very durable substance. However it is still under constant assault from sun, rain, temperature changes, salt in winter, physical stresses...

Wear and tear!

Our teeth are also subjected to extraordinary stresses. Chewing itself puts high repetitive mechanical stresses on teeth. There are drastic temperature changes as we bounce between the heat of the corn on the cob and the burger, to the cold of the salad, or the iced tea. There are sugars and salts and hard popcorn kernels and gritting when we hit a baseball. (Next time you go to the batting cages, take note of how hard you grit your teeth together as bat connects to ball. It's astonishing!) Some of us even grind our teeth every night. Or during the day, when your boss wants those TPS reports yesterday and you got a letter from the IRS calling for an audit and your son sends you a cryptic text that seems to indicate that the water heater is leaking but he's going to the skate park now...

It all adds up, and yet the biggest threat to the health of our teeth is sugar. Our Caries Clock explains it all quite well:

High frequency sugar intake is the overwhelming causative factor of cavities. They can occur anywhere on teeth but there are some main areas where they are most common.

Interproximal or between-teeth cavities can really damage a tooth; here is a large, obvious one:

Yet perhaps the most common place for cavities is in the grooves on the tops of our back teeth. My own tooth, no cavity in those grooves on the biting surface:

Those deep grooves are the other main place that cavities occur. Many years ago, in the 1920's and 30's, when the roles of sugar intake and oral hygiene in cavity formation were not so well known, it was estimated that over 95% of back teeth present in the American population either had cavities or fillings in their grooves.

There are many preventive strategies aimed at reducing the chance of tooth decay. The greatest is to limit the frequency of refined sugars in one's diet, a la our Caries Clock. Another is cleaning the bacterial plaque from our teeth each day, and seeing a dentist and hygienist on a regular schedule for professional cleaning of the surfaces of each tooth. We can also employ fluoride to strengthen the enamel against cavities.

Another way of protecting those grooves from decay is the dental sealant. This is a composite resin filling-like material. The difference between a sealant and a restoration is that there is no drilling, and thus no need for anesthesia, when a sealant is placed. They are essentially painted on to the tooth and stay there because of the power of dental adhesion. We can make our dental materials stick very well indeed these days:

Here are views of sealants in place on two six-year molars, an upper and a lower one, while orthodontic bands are in place:

The grooves are blocked out, sealed, and it makes it very difficult to get a cavity in the top surface of the teeth. Not impossible, any system can be overloaded, in this case with too much constant sugar use. But it's nearly impossible to get a cavity in the grooves of a tooth with a sealant in place.

Between-tooth cavities? For now, there is not a predictable way to prevent decay. Flossing and moderation in diet are the best strategy. But on the biting surfaces of back teeth? Sealants rock.

Comments

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Ahh, I see Rick—the sealant is the same material you get in those Fix-A-Leak aerosol cans for sealing tire blowouts. I have a can around; I'll use it next time I feel my dental coverage has been compromised.

Hey, how often do you go to the batting cages? Can you hit a curve ball?

Tom:
Shhh! We don't want that Sibilant Sealant Secret to get out! Before you know it, us dentists will be submitting our sealant claims to auto insurance, rather than dental!
And, about the batting cages- though I very much enjoy baseball and my daughter's softball games as a spectator, I was way too traumatized over my poor performance in the schoolyard to ever make a serious attempt at the game as an adult. I could hit the dang ball now and again, but my fielding was abysmal.
Once, in sixth grade, whilst choosing up teams, my classmates (in)famously picked a guy who still had his broken leg in a cast before me, just to make a point.
Ouch.

Well, Jenna, it is VERY long-term temporary, in that sealants act like bonded fillings, and last for a good number of years. Plus, many studies indicate that even once the visible sealant material is worn away by chewing, there is a strong protective effect in the deep grooves provided by the bond remaining there for an even longer time.

Sealants could be replaced at intervals in adults, but we rarely do. Epidemiology is the reason. If an adult has a filling in a back tooth, then the original decay has already happened and the filling takes the place of a sealant. If the natural tooth grooves are still intact, never having had a cavity, then the chances are pretty low that it will get one, sealed or not.

Unless an adult starts to ingest frequent high amounts of sugar-containing foods and drinks. See our magnificent Caries Clock for more in the way of an explanation!

Cracked and/or chipped teeth can ruin a beautiful smile. Tooth sealants can cover up the cracks and make your teeth look as good as new. However, it's still better to prevent tooth damage by flossing and brushing.